[FFmpeg-devel] [PATCH 1/4] avformat/hlsenc: Add init_program_date_time so start time can be specified

[David Johansen]

On Fri, Oct 27, 2023 at 4:58 AM <epirat07 at gmail.com> wrote:

> On 27 Oct 2023, at 5:59, Dave Johansen wrote:
> >  @item second_level_segment_index
> >  Makes it possible to use segment indexes as %%d in hls_segment_filename
> expression
> >  besides date/time values when strftime is on.
> > diff --git a/libavformat/hlsenc.c b/libavformat/hlsenc.c
> > index 4ef84c05c1..5dfff6b2b6 100644
> > --- a/libavformat/hlsenc.c
> > +++ b/libavformat/hlsenc.c
> > @@ -212,6 +212,8 @@ typedef struct HLSContext {
> >      int64_t recording_time;
> >      int64_t max_seg_size; // every segment file max size
> >
> > +    char *init_program_date_time;
> > +
> >      char *baseurl;
> >      char *vtt_format_options_str;
> >      char *subtitle_filename;
> > @@ -1192,6 +1194,25 @@ static int hls_append_segment(struct
> AVFormatContext *s, HLSContext *hls,
> >      return 0;
> >  }
> >
> > +static double parse_iso8601(const char *ptr) {
> > +    struct tm program_date_time;
> > +    int y,M,d,h,m,s;
> > +    double ms;
> > +    if (sscanf(ptr, "%d-%d-%dT%d:%d:%d.%lf", &y, &M, &d, &h, &m, &s,
> &ms) != 7) {
> > +        return -1;
> > +    }
> > +
> > +    program_date_time.tm_year = y - 1900;
> > +    program_date_time.tm_mon = M - 1;
> > +    program_date_time.tm_mday = d;
> > +    program_date_time.tm_hour = h;
> > +    program_date_time.tm_min = m;
> > +    program_date_time.tm_sec = s;
> > +    program_date_time.tm_isdst = -1;
> > +
> > +    return mktime(&program_date_time) + (double)(ms / 1000);
> > +}
> > +
> >  static int parse_playlist(AVFormatContext *s, const char *url,
> VariantStream *vs)
> >  {
> >      HLSContext *hls = s->priv_data;
> > @@ -1257,24 +1278,11 @@ static int parse_playlist(AVFormatContext *s,
> const char *url, VariantStream *vs
> >                  }
> >              }
> >          } else if (av_strstart(line, "#EXT-X-PROGRAM-DATE-TIME:",
> &ptr)) {
> > -            struct tm program_date_time;
> > -            int y,M,d,h,m,s;
> > -            double ms;
> > -            if (sscanf(ptr, "%d-%d-%dT%d:%d:%d.%lf", &y, &M, &d, &h,
> &m, &s, &ms) != 7) {
> > +            discont_program_date_time = parse_iso8601(ptr);
> > +            if (discont_program_date_time < 0) {
> >                  ret = AVERROR_INVALIDDATA;
> >                  goto fail;
> >              }
> > -
> > -            program_date_time.tm_year = y - 1900;
> > -            program_date_time.tm_mon = M - 1;
> > -            program_date_time.tm_mday = d;
> > -            program_date_time.tm_hour = h;
> > -            program_date_time.tm_min = m;
> > -            program_date_time.tm_sec = s;
> > -            program_date_time.tm_isdst = -1;
> > -
> > -            discont_program_date_time = mktime(&program_date_time);
> > -            discont_program_date_time += (double)(ms / 1000);
> >          } else if (av_strstart(line, "#", NULL)) {
> >              continue;
> >          } else if (line[0]) {
> > @@ -2867,7 +2875,7 @@ static int hls_init(AVFormatContext *s)
> >      char *p = NULL;
> >      int http_base_proto = ff_is_http_proto(s->url);
> >      int fmp4_init_filename_len = strlen(hls->fmp4_init_filename) + 1;
> > -    double initial_program_date_time = av_gettime() / 1000000.0;
> > +    double initial_program_date_time = hls->init_program_date_time ?
> parse_iso8601(hls->init_program_date_time) : av_gettime() / 1000000.0;
>
> As parse_iso8601 parsing user input can fail, it should properly report
> the error and fail. Especially given that it does not accept all variations
> of ISO-8601 date/time IIUC.
>
> It might be confusing if the user specifies a time, forgets the
> milliseconds and it will just silently not use the option at all?
>

I added improved parsing and error reporting. I sent in the patch, but is
there a way for me to tie it to this patchset in the future?